If the panelling is wood (and not plastic), it will expand and contract, thus, cracking on you. Sometimes, joint compound will crack for a number of reasons: Dried too fast, put on too thick (instead of many thin layers), not properly mixed, or wrong application. I've put joint compound on panelling before but I painted it right afterwards. (No wallpaper was in the picture, and the paneling was oak.) Great fluxuations in temperature may crack the compound too.
You can try to apply a thin coat of joint compound over the cracks, and let it dry for at least a day. Keep the temperature around 70 degrees (+/-). If the house is real dry, that may add to the problem too.